The ties of blood

The adverse health effects from air pollution, for example, are quite well known. But we do not know how exposure may develop into diseases over the course of a whole life. A new research centre at Aarhus University will attempt to link a unique database with state-of-the art approaches in order to uncover the connection between blood and the surroundings by looking for biomarkers that can provide a preliminary understanding of how the body is affected by modern life.

This was the conclusion of a DCE study from 2014 that showed the impact of air pollution on public health in Denmark’s second-largest city.

Wood-burning stoves. Candles. Morning traffic in cities. Indoor climate Open or closed windows. The media give lots of coverage to air quality and how it affects people’s health and well-being. The same is true for the world of science, where the effects on humans of particulate matter and nitrogen oxides (NOx), for example from traffic and industrial activities in cities have been well described. Our understanding of how harmful substances move around in our environment is also well advanced.

But the negative impacts on our health is just one side of the coin. On the other side is a significant gap in our understanding: We don’t know why and how, from a physiological point of view, we fall ill. If we can gain more insight into these aspects, we may discover ways to avoid the consequences in the long term.

The BERTHA (Big Data Centre for Environment and Health), research centre at Aarhus University is now trying to launch a research project that will look for specific and sensitive biomarkers in blood samples from Danish blood donors.

"This linkage has not been investigated before, but we’re in a unique position to take the first steps here at BERTHA. Our goal is to identify a broad and precise panel of biomarkers showing how we’re affected by air pollution, so that, in the long term, we will be able monitor the direct effects on public health. Our hope is that in future we will be able to identify disease formation earlier and take preventive measures in due time,” explains Professor Christian Erikstrup, who is heading the project.

A knowledge bank without equal

Biomarkers is a generic term for substances that can be measured in our blood, for example. Many harmful external influences change the processes in our body, and this can be measured in our blood. Biomarkers tell us something about our specific state of health. For example, they may indicate a person’s risk of cardiovascular diseases, diabetes, infections, inflammations or cancer.

This is why biomarkers are the main focus area for the BERTHA group's work to investigate whether exposure to air pollution leads to measurable changes in inflammation markers. The aim of their work is to generate a better understanding of the causality between the effect of pollution on the body and on the mechanisms leading to diseases.

"If we can find a correlation between exposure to air pollution and an inflammation measured in a blood sample from a person who is otherwise healthy, this can provide new knowledge on how pollution affects our body," says Christian Erikstrup;

"Similar approaches have been used in projects conducted in the Far East and these have demonstrated possible correlations between certain biomarkers and pollution levels. However, the massive level of pollution in some areas of the world alone means that results from other countries cannot simply be transferred to Denmark. Thanks to the great effort of Ole Hertel and Carsten Bøcker, professors at AU, Denmark has very detailed knowledge about air pollution levels at different times throughout the country. Along with the possibility to measure biomarkers in blood donors, this makes the study truly unique."

The idea is to measure a wide range of biological markers from the biobank in the Danish Blood Donor Study (DBDS). Samples from the biobank enable measurements from donors all across Denmark, as well as measurements from the same donors at times with different levels of air pollution.

Pure insight

Up to 110,000 donors between 18 and 67 are participating in the Danish Blood Donor Study. Blood samples have been collected, and each donor has answered a set of questions about their health, lifestyle, etc. This data can serve as a solid foundation for the work that the research group wants to initiate.

The samples from the DBDS provide data from across Denmark, and it is possible to make new measurements on the same donors at times with different levels of air pollution.

"Blood donors are in many ways the perfect starting point, because they have to be in good health to be approved as donors. This gives us an excellent basis to learn more about the impact of air pollution on healthy individuals," says Christian Erikstrup.

A focus point for the work are so-called cytokines: proteins that serve as a kind of messenger for the body's immune system, and whose presence in a person's blood indicates a possible inflammation in the body. In a donor, the level of cytokines is likely to be low, and an increase in this level could indicate a response to an exposure.

The combination of DBDS data and knowledge from other parts of the BERTHA research centre about the geographical location and temporal duration of air pollution will thus form the basis of a preliminary understanding and monitoring of air pollution effects on public health. This is based on the assumption that, if there is a change in the blood donor samples at a certain place at a time of increased pollution levels, this can be measured in the samples thus providing new knowledge about the derived effect.

“Throughout our lives, we are faced with different impacts that may be good or bad for our health. Our hope is to be able to look at a person’s life and derive valuable knowledge about how health is affected by these impacts. We look forward to commencing this work once the necessary approvals are in place," says Christian Erikstrup.